1. Field of the Invention
The invention relates to a device for performing artificial respiration on a patient.
2. The Prior Art
Devices of this type are known as resuscitators. These are used within the medical field when a patient is unable to breath correctly, or when the patient does not breath at all, e.g., because of deep unconsciousness. Such devices are used not only at hospitals, but also in many other connections where first aid equipment finds application.
Such a device comprises a container which defines an inner volume with respect to the ambient, and which is provided with a first opening accommodating a valve arrangement which allows inflow of air and/or other gases from the outer area to the inner area, a second opening in connection with which there is provided a valve arrangement which allows outflow from the container and prevents inflow to the container through the second opening, and a mouthpiece adapted to be fitted over the openings of a patient""s air passages for the delivery of the air and/or gas flowing out of the container to the patient. Using a known device, the mouthpiece is held against the patient""s face by one hand, while the container is squeezed by the other hand to force the air or gas present in the container out of the container.
However, it has been found that such devices for performing artificial respiration on a patient, where such devices are in the hands of persons having no or only little practice, does not provide satisfactory breathing assistance. The reason is that it may be difficult to hold the mouthpiece correctly relative to the patient""s face by one hand to ensure that the area around the air passages is sealed completely, so that no air flows out along the edge of the mouthpiece, while squeezing the container by the other hand to press the air and/or gas present in the container into the patient. Part of the air or gas pressed out is thus lost to the ambient. Clearly, this may have serious consequences for the patient""s health.
The object of the present invention is to provide a device of the type mentioned in the foregoing, by means of which it may be ensured with greater certainty, also when unpractised persons use the device, that the patient receives the maximum intended amount of the air pressed out of the container.
This is achieved according to the invention in that an expansible means is provided in the container and adapted to expand upon action on the outer area to displace air or other gases in the container out through the second opening.
When such an expansible means is arranged in the container, it is no longer necessary to squeeze the container by one hand to force the air present in it out through the second opening and into the patient. It is thus possible to use both hands for holding the mouthpiece relative to the patient""s face, while expansion of the expansible means displaces the air from the interior of the container and into patient, and it is thus ensured that air does not, or only to a limited extent, get past the edges of the mouthpiece. The intended amount of air is thus delivered to the patient.
In an expedient embodiment, the container may be compressible, as the wall of the container is elastic and flexible, so that, if desired, the device may also be used under more controlled conditions, e.g. at a hospital where experienced staff is present to hold the mask of the device in engagement with the patient""s face. After manual compression of the container, air or oxygen is conventionally sucked into the inner volume because of the elasticity of the wall.
In an expedient embodiment, the expansible means is thus formed by an inflatable means. The means involved may be a means which is inflatable by means of the assistant""s expiration air. The interior of the expansible means is hereby isolated from the interior of the container, and there is thus no risk of contagious diseases being transmitted via this device.
The container used may be of the known compressible type or may be a rigid or relatively rigid container. In connection with the invention it is exclusively required that the container used can present a counterpressure on the expansion of the expansible element, and that the container is essentially dimensionally stable when air or gas is sucked in from the ambient.
Particularly expediently, the expansible means is a self-contractible means. Hereby the self-contractible means will suck in air through the first opening during its self-contracting function. The self-contracting force of the expansible means must be sufficient to open the valve arranged at the first opening.
In this connection the expansible means may be formed by a bag of a flexible sheet material and an elastic material, e.g. an elastic net, arranged on the outer side of this sheet material, a balloon of an elastic rubber material or a bag of a flexible sheet material formed with corrugations or folds which, when relieved, contract the bag.
The expansible means preferably comprises a connecting element adapted to cooperate with a complementary connecting element arranged in an opening in the container. The opening in the container for the connecting element of the expansible means is preferably arranged such that the assistant, when performing the artificial respiration, can get access to the mouthpiece with his mouth.
The invention moreover relates to a container for use in connection with a resuscitator described in the foregoing. Such a container comprises an opening through which a gas can flow into the container, an opening through which a gas can flow out of the container, and an opening through which an expansible means may be inserted into the container. If this container is used in connection with a normal resuscitator which operates by compression by hand, this opening for the insertion of an expansible means may be closed by a cap. In this connection the container must satisfy the above-mentioned criteria for such a container.
The invention moreover relates to an expansible means for use in a resuscitator as described in the foregoing. Such an expansible means comprises a mouthpiece for the injection of air. The expansible means is expediently shaped as described in the foregoing, viz. either as a bag of a flexible sheet material and an elastic material, e.g. an elastic net, arranged on the outer side of it, a balloon of an elastic rubber material or a bag of a flexible material formed with corrugations or folds which, when relieved, contract the bag.